Various types of collapsible furniture are known in the art. U.S. Pat. No. 2,361,875, for example, discloses a stool of one-piece construction which may be folded from a single flat sheet of material. To form the article, a first portion of the sheet is folded to form a triangular pedestal; two other, identical portions are then folded over the pedestal in interlocking relationship therewith to retain the pedestal in its folded configuration.
However, the design according to U.S. Pat. No. 2,361,875 has several disadvantages. The base or pedestal is held together only through engagement of interlocking tabs of the seat portions on a top end thereof. There is no integral structure for holding together the lower end of the base. Additionally, there is very little support provided by the base around the perimeter of the seat. This makes the stool undesirably unstable and easy to tip over and, in addition, renders the seat easily and unexpectedly deformable under the weight of a person or child sitting thereon.
Another type of known foldable stool is disclosed in U.S. Pat. No. 2,390,546. However, this prior art stool has the disadvantage of requiring the use of staples in its assembly. This stool does offer a slight improvement over the article of U.S. Pat. No. 2,361,875 in that it includes two, instead of only one, triangular support pedestals or legs. However, it suffers a similar disadvantage with the stool of U.S. Pat. No. 2,361,875 in that both leave large portions of the seat (i.e. about 50% or more) unsupported and, thus, relatively easily deformable when one attempts to sit on the stool, especially if the articles are formed of a relatively lightweight material such as reinforced paper or cardboard.
A substantially safer and more practical design for a foldable stool is illustrated in my U.S. Design Pat. No. Des. 236,673. The stool therein disclosed has an octagonal seat with four box-like legs for support. Not only is the seat better supported with this design but it is far less likely to tip over under load. This design, however, is of two piece construction. Thus, as shown in FIG. 3 of U.S. Design Pat. No. 236,673, a second member is employed to interlock with notches in each of the four legs of the stool and thereby retain the stool in its folded or assembled condition.
A need therefore exists for a safe, sturdy, lightweight, foldable stool which can be formed in its entirety from a single, unitary sheet of material without the use of supplemental securement members or fasteners such as staples or glue. Furthermore, a need exists for a foldable stool or table which can be made from lightweight materials, such as paper, cardboard or corrugated cardboard and the like, while having good stability and strength against deformation under normal load conditions.